Method for making an ordered magnetic alloy

Abstract

A method for making an ordered magnetic alloy includes (a) providing a thermally conductive base having opposite first and second surfaces; (b) forming a thermal barrier layer on the first surface of the thermally conductive base; (c) forming a disordered magnetic alloy layer on the thermal barrier layer, the disordered magnetic alloy layer being made from a disordered alloy which contains a first metal selected from Fe, Co, and Ni, and a second metal selected from Pt and Pd; and (d) after step (c), applying a transient heat to the thermally conductive base to cause rapid thermal expansion of the thermally conductive base, which, in turn, causes generation of an in-plane tensile stress in the disordered magnetic alloy layer.

What is claimed is: 
     
       1. A method for making an ordered magnetic alloy, comprising:
 (a) providing a thermally conductive base having opposite first and second surfaces; 
 (b) forming a thermal barrier layer on the first surface of the thermally conductive base; 
 (c) forming a disordered magnetic alloy layer on the thermal barrier layer, the disordered magnetic alloy layer being made from a disordered alloy which contains a first metal selected from Fe, Co, and Ni, and a second metal selected from Pt and Pd; and 
 (d) after step (c), applying a transient heat to the thermally conductive base to cause rapid thermal expansion of the thermally conductive base, which, in turn, causes generation of an in-plane tensile stress in the disordered magnetic alloy layer to thereby order the disordered magnetic alloy layer, 
 wherein the application of the transient heat in step (d) is conducted by heating the thermally conductive base from an initial temperature to a phase-changing temperature T a  at a heating rate ranging from 20 to 50° C./sec, such that 0.13T m <T a <0.35T m , where T m  is the melting point of the disordered alloy, and 
 wherein the application of the transient heat in step (d) is conducted by heating the second surface of the thermally conductive base with a light source having a wavelength ranging from 400 nm to 1100 nm. 
 
     
     
       2. The method of  claim 1 , wherein the thermally conductive base is made from Si, the thermal barrier layer being made from silica, the disordered magnetic alloy layer being ordered to form an ordered magnetic alloy layer having (001) preferred orientation. 
     
     
       3. The method of  claim 1 , wherein the thickness of the thermally conductive base ranges from 1.5 μm to 650 μm, and the thickness of the thermal barrier layer ranges from 10 nm to 400 nm. 
     
     
       4. The method of  claim 3 , wherein the first metal is Fe, and the second metal is Pt. 
     
     
       5. The method of  claim 4 , wherein the thickness of the thermally conductive base ranges from 1.5 μm to 450 μm, and the thickness of the thermal barrier layer ranges from 10 nm to 200 nm, and wherein 0.26T m <T a ≦0.30T m . 
     
     
       6. The method of  claim 4 , wherein the disordered magnetic alloy layer further contains an oxide, the thickness of the thermally conductive base ranging from 450 μm to 650 μm, and wherein 0.18T m <T a ≦0.20T m . 
     
     
       7. The method of  claim 4 , wherein the disordered magnetic alloy layer further contains an oxide, the thickness of the thermally conductive base ranging from 200 μm to 300 μm, and wherein 0.13T m <T a ≦0.20T m .